your site looks nice. great for your product.
You may want to notice, however, that there is an 'edit/delete' link at the bottom right corner of your post here. You should use that instead of reposting with the same question.
You should probably target a specific audience and put your link where they shop. The general public probably wouldn't buy lights as often as say, a contractor or maintenance dept. of a large corp.
Your main site design is not bad, but on my end, I can see why you are not getting many orders through ... your osCommerse area is having issues with your coding. Check out the screenshot below. As for your ppc at google, the key is having the right keywords to get the right customers to your site. Some might just be doing research. The other problem is that unless you have some rare bulbs you can't find anywhere else, there are quite a few places that sell bulbs (including the corner shop where you don't have to wait for them to be shipped). It's a tough market on the web, you just have to keep working at marketing yourself as better then your competition.